The present invention relates to an air bag apparatus for lateral collision of an automobile.
As an air bag apparatus for lateral collision of an automobile, there is one of a type where an air bag is developed forwards from an outer end portion, in a vehicle transverse direction, of a seat back to protect a vehicle occupant (refer to Japanese Patent Application Laid-Open No.9-136598 as a similar art).
An air bag apparatus of this type has a structure where an air bag and an inflator are accommodated in a metallic container opened at a front side thereof. The air bag breaks through the seat back to develop forwards by gas injected from the inflator.
However, such a prior art is disadvantageous regarding weight because a metallic container is used for accommodating an air bag. Also, when a vehicle occupant sits on a seat, the occupant feels a foreign matter at his/her back because the metallic container is hard. Furthermore, since the air bag may be injured by end edge of an opening portion of the metallic container, it is necessary to conduct a heming process on the end portion of the opening portion, which results in trouble work in manufacture of the metallic container.
The present invention has been achieved in view of such a prior art, and provides an air bag apparatus for lateral collision of an automobile which can be reduced in weight and does not give a feeling of foreign matter to the back of a vehicle occupant.
The aspect of the present invention is an air bag apparatus comprising a housing formed of a synthetic resin and fixed to an outer end portion, in a vehicle transverse direction, of a seat back, an air bag and an inflator accommodated in the housing, and a splitting-opening portion which is configured by end portions opposed to be engaged with each other when the air bag is accommodated in the housing. The air bag projects through the splitting-opening portion as the air bag is expanded and developed.
According to the above arrangement, as a housing formed of the synthetic resin is used instead of a metallic container, the weight of the air bag apparatus can be reduced. Also, as the housing is deformable when it is pressed, there is no fear that the air bag apparatus gives a feeling of foreign matter to the back of a vehicle occupant. Since the splitting-opening portion where the end portions are engaged with each other is provided in the housing, the air bag is developed from a predetermined portion (the splitting-opening portion) of the housing without fail, so that the developing behavior of the air bag is made stable.
The housing may be formed in one piece covering peripheries of the air bag and the inflator to accommodate the same, and the splitting-opening portion can be formed by engaging end portions of the housing of the one piece with each other.
According to the above arrangement, as the housing is one piece, it can easily be manufactured.
The splitting-opening portion may have a structure where a hook portion formed at one end of the housing and a recessed portion formed at the other end thereof are engaged with each other.
According to the above arrangement, since the splitting-opening portion is configured by the hook portion formed at the one end of the housing and the recessed portion at the other end, an engaging force of the splitting-opening portion can easily be adjusted by changing the shapes and sizes of the hook portion and the recessed portion. Accordingly, the engaging force of the splitting-opening portion can easily be set to be an optimal magnitude in which the splitting-opening portion is not opened easily and it is opened securely when the air bag is developed.
The splitting-opening portion may be provided at an outer side position, in the vehicle transverse direction, of the housing fixed to the seat back.
According to the above arrangement, as the splitting-opening portion is provided at the outer side position, in the vehicle transverse direction, of the housing, the splitting-opening portion is positioned along the longitudinal direction of a vehicle. Accordingly, the pressure acting on the splitting-opening portion from the back of the vehicle occupant due to a normal use of the seat back acts so as to engage the hook portion and the recessed portion with each other, so that the splitting-opening portion is prevented from being opened due to a normal use of the seat back.
The splitting-opening portion may be arranged at the rear side of the outer side position of the housing.
According to the above arrangement, the splitting-opening portion is arranged at the rear side of the outer side position, the vehicle occupant side face of the housing opened to extend forward by development of the air bag is elongated. Accordingly, the occupant side face of the housing which has extended forward services as a guide for developing the air bag forward, and also serves so as to prevent the vehicle occupant and the air bag expanding rapidly from directly contacting with each other.